Vacuum tube device



April 16. 1940- R. scHARr-'NAGEL 2,197,511

VACUUM TUBE DEVICE Filed Feb. 2l, 1959 Ceram C Material, 5 4- 3 4. E5l

Patented Apr. 16, 1940 UNITED STATES PATENT OFFICE VACUUM TUBE DEVICEApplication February 21, 1939, Serial No. 257,590 In Germany February21, 1938 l Claim.

'I'he present invention relates to vacuum tube devices, and morespecifically to electron discharge tubes having coaxially relatedtubular lead-in conductors for the electrode system thereof.

It is known in connection with vacuum tube devices to employ a coaxialconductor system and to seal such system either to any suitable portionof the tube envelope, or to a closing mem- U ber intimately joined withsaid envelope. Such sealing is frequently carried out by the agency ofdisc-shaped and annular members of glass or of a ceramic material whichare placed adjacent the tubular conductors of the coaxial system so thatl vacuum seals between the different parts may be made by means of aheat treatment. This method, however, suffers under the disadvantagethat the vitreous material used for the sealing operation is dividedinto several individual portions 20 separated from `one another by thetubular conductors extended therethrough so that diilerent tensionalproperties are imparted to the various members. It is thus obvious thatthe heretofore mentioned conditions might easily introduce diiii- 25culties in the device or devices under consideration.

The present invention has for its object to eliminate drawbacks of theaforementioned kind. 'I'he tubular conductors are, according to the 30main feature of my invention, provided with a number of aperturescircumferentially arranged thereon in radial relation to each other andin` (Cl. Z50-27.5)

is placed in the centralr opening of the smaller conductor l, whileceramic members 4 and 5 of annular shape are provided between the twoconductors and around the outer surface of the larger conductor 2,respectively` The last men- 5 tioned annulus 5 is sealed to the upperrim of the tube envelope 6. The three members 3, Il and 5 are xed in thesame geometric plane. The tubular conductors I and 2 may be chrome-ironpipes, for example.

As taught by the main feature of my invention, each conductor of thecoaxial system is provided with a number of apertures eircumferentiallyarranged in radial relation to each other in one geometric plane. Theseapertures are indicated l5 at l in the accompanying drawing. A fluidvitreous sealing material poured onto the upper surface of either of themembers 3, 4 and 5 for producing a vacuum seal between the severalmembers of metal and ceramic material is allowed to iiow through theseapertures so as to form a continual undivided glass coating 8 of uniformtensional properties, which will not give rise to any diiiiculties ofthe heretofore mentioned nature.

What is claimed is:

A vacuum tube comprising an envelope, an electrode arrangement therein,a coaxial conductor system having an inner and an outer tubularconductor electrically connected with said electrode arrangement, andmeans to aiiix said conductor system to said envelope comprising a discof ceramic material in said inner conductor at right angles to the axisthereof, a first annular ceramic member in the space between said innerand said outer conductor, a second annular ceramic member arranged aboutsaid outer conductor and in one plane with said disc and said firstannular member, a row of radial apertures in each of said tubularconductors located in a further plane parallel with and slightly abovesaid first mentioned plane, and a layer of vitreous material on theupper surfaces of said disc and said annular members in the said furtherplane and extending through said apertures.

RUDOLF SCHARFNAGEL.

